A trust of massa



Patented May 26, 1931 UNITED, STATES PATENT OFFICE MASSACHUSETTS,ASSIGNOR TO LUDELOW LOW, MASSACHUSETTS, A TRUST OF MASSA- LINEN SHOETHREAD Ho Drawing.

This invention relates to an improved linen shoe thread intended andadapted for the sewing of shoes.

The new linen shoe thread of the present invention is a linen threadspecially treated to preserve it against the deteriorating conditions towhich it is subjected when used in shoes. More particularly, theinvention relates to an unboiled linen thread with its normal content ofpectin, hemi-cellulose and other non-cellulose constituents, which ispreserved so that it is adapted for use, for example, as a welt threadas a substitute for the boiled linen thread or cheaper cotton thread nowcommonly employed for shoe manufacture.

In shoe manufacture the uppers are sewed to the welts by shoe threadwhich is usually linen thread for the better grades of shoes and cottonthread for the cheaper grades of shoes. Similarly, in sewing the outeredges of the soles of shoes linen thread is used for the better gradesof shoes and cotton thread for the cheaper grades.

The linen thread which is commonly used for shoe thread is a so-calledboiled thread, made by boiling the yarn from which the thread is made,in a dilute solution of caustic soda and soda ash which dissolves outthe greater part of the pectin, hemi-cellulose and non-celluloseconstituents, giving what is known in the trade as a boiled yarn, fromwhich linen shoe thread is now made. In this way the flax is freed moreor less completely from the non-cellulose constituents which readilyundergo deterioration or decomposition by micro-organisms; and it hasheretofore been considered necessary to remove such constituents more orless completely in order to produce a satisfactory linen shoe thread.

The shoe thread of shoes is subjected to conditions which favor andpromote deterioration or decomposition of the shoe thread, andparticularly of shoe thread which contains any substantial amount ofreadily decomposable constituents which are decomposed by mold orbacterial action. Shoes in the ordinary course of wear come intocon tactwith street dirt, dust, mud, etc., and it is well known that ordinarystreet dirt and Application filed September 29, 1930. Serial No.485,328.

dust, etc., are contaminated with or contain numerous micro-organisms,such as molds, bacteria, etc. In rainy weather shoes come in contactwith wet sidewalks and streets or with wet dirt or mud and the waterpenetrates the'shoe to a greater or less extent, carrying with itcontaminating micro-organisms. Leather shoes are also kept more or lessmoist byperspiration, particularly in the summer time and in humidweather. When shoes become wet or moist either through rainy weather orthrough perspiration with improper opportunity for drying out, theconditions are favorable for the rapid growth and development of moldsand bacteria which are present in shoes which have been Worn for anylength of time. When shoes are worn day after day and particularly inrainy weather or in hot, humid weather and are not permitted to dry outproperly favorable conditions are presented for development and growthof destructive micro-organisms. Even boiled linen thread and cottonthread are not immune from such micro-organisms.

I have investigated the action of microorganislns from street dirt onunboiled linen shoe thread and I have found that under favorableconditions of moisture and temperature such threads undergoes rapiddeterioration. I have found, however, that by incorporating in theunboiled linen thread a suitable disinfectant the thread can bepreserved and made resistant to such micro-organisms and can thereby bemade available for use as a valuable substitute for boiled linen shoethread and for cotton shoe thread. I have also found that even theboiled linen thread can be improved in its resistance to deteriorationby similarly incorporating a suitable disinfectant therein.

The disinfectants which I employ in the treatment of the shoe thread aredisinfectants which are of a more or less permanent character and whichremain in the shoe thread and impart to it. resistance to decompositionor deterioration by such destructive micro-organisms as are found instreet dirt,

mud and the like with which shoes are continually brought in contact inevery day use. The dlsinfectant may kill or destroy the moulds, bacteriaor micro-organisms by reason of its toxic poisoning action, or thedisinfectant may produce a state of suspended growth by reason of atoxic poisoning action less drastic than that required to kill ordestroy the organisms; or the disinfectant may kill or destroy themoulds, bacteria or micro-organisms or produce a state of suspendedgrowth by reason of its dehydrating action on the material treated or onthe organisms themselves. Certain disinfectants may exhibit a combinedpoisoning and dehydrating action. Merely boiling the thread withoutalkali, whereby the thread is subjected to a sterilization by heatalone, is not sufficient to preserve the thread against attack bymicro-organisms normally accompanying unboiled thread, or to be found instreet dirt or the like.

The disinfectant which I have f und particularly advantageous andeffectiv is a dyestuff known in the trade as Brilliant Green, whichbelongs to the triphenyl methane series of coloring matters and ischemically designated as the sulfate or double zinc chloride of tetraethyl diamido-triphenyl-carbinol. Other dyestuffs which have adisinfecting and preservative action can be used, including otherdyestuffs of the triphenyl methane series which havesuch a disinfectingand preservative action. Othersubstances than dyestuffs can also be usedas disinfectants or preservatives, including sodium silico fluoride,sodium phenyl phenate and certain copper salts which have a disinfecting and preservative action.

The incorporation of the disinfectant with the thread can take place atdifferent stages of manufacture. It may be incorporated, for example,during the spinning of the yarn by using what is known as the dampspinning process and moistening the yarn with a solution of thedisinfectant. The thread can also be dipped in a solution of thedisinfectant after it has been formed. The method of incorporation whichI consider particularly advantageous is by passing the yarn through abath of the disinfectant as the plies or strands of yarn are drawnthrough the twisting machine tomake the finished thread. The yarns arecommonly passed through a water bath to wet them for this twistingoperation and the incoporation of the disinfectant in the water bathenables the thread tobe manufactured in the ordinary manner without anyadditional operations but nevertheless with satisfactory incorporationof the disinfectant in the yarn and thread. In such case only the usualdrying of the thread is needed to complete its manufacture.

The amount of disinfectant which is incorporated in the thread will varywith different disinfectants and may vary with the same disinfectant. Inthe case of Brilliant Green incorporation of as little as one part ofthe dye in ten thousand parts of the thread by weight is effective inretarding mold and bacterial growth, but larger amounts can be used,particularly for tropical climates or other places where the shoes aresubjected to unusually severe conditions promoting deterioration ordecomposition of the linen thread. In some cases as much as 1% or moreof antiseptic may be incorporated in the thread although ordinarily amuch smaller amount will be suificient.

The improved unboiled linen shoe thread of the present invention hasimportant advantages in its method of manufacture as compared with theordinary boiled linen thread which is now used. The boiling operationwhich requires special equipment and chemicals and requires aconsiderable period of time for the boiling operation'can be eliminatedthereby economizing in cost of equipment, in cost of chemicals, in thetime required for making the thread, and in the labor and expenseinvolved in its manufacture. While the boiling operation removes up to20% or more of the weight of the flax, the entire weight of the flax isretained in the new unboiled thread which is nevertheless of a strengthcomparable with that of boiled thread, thereby in effect very materiallyincreasing the amount of thread which can be manufactured from the sameamount of flax. That part of the flax which it has heretofore beenconsidered necessary to remove in the boiling operation and which,unless removed, causes the thread as a whole to undergo rapiddeterioration is so preserved by the incorporation of the disinfectantin the thread, according to the resent invention, that it remains as avalua le part of the thread, making the thread as a whole comparable instrength and usefulness with boiled thread of equal weight which wouldrequire a considerably greater amount of flax for its manufacture.

Inasmuch as the disinfectant or preservative can readily be incorporatedin the thread as a part of its process of manufacture without adding tothe cost of manufacture except for the small cost of. the antiseptic orpreservative, the improved unboiled shoe thread can be manufactured at amaterially less expense than the ordinary boiled shoe thread, thusenabling an increased yield of shoe thread to be produced from the sameamount of flax and at less cost of manufacture.

I have found that even boiled linen shoe thread can be improved in itsresistance to deterioration by similarly incorporating a I disinfectantor preservative in it, thereby gi v ing an improved boiled linen shoethread; but in the case of such a boiled shoe thread the cost ofmanufacture is increased by the boiling operation and the amount of shoethread produced from the flax is correspondingly 'thread will retainlonger life to the shoe,

decreased as compared with the improved unboiled shoe thread abovedescribed. While therefore the invention in its broader aspects includesan improved boiled shoe thread, the unboiledlinen shoe threadof thepresent invention has many advantages, bein distinguished from boiledshoe threads iy its content of all of the normal constituents of theflax fiber as well as by the presence of the preservative ordisinfectant, by the greater yield of shoe thread produced from the sameamount of flax fiber, by its materially decreased cost of manufacture,and in other respects such as those above referred to.

The advantages which the improved shoe thread of the present inventionpresents will be obtained when the shoe thread is used in themanufacture of shoes and when the shoes are then worn and subjected tothe varying conditions of use where theyv come into contact with streetdirt, dust, mud, etc. and become infected with various micro-organisms,and when conditions of moisture and temperature are favorable for thegrowth of such micro-organisms. Thus, even where the shoes remain moistand warm for considerable periods of time, as in rainy or humid weather,or where proper opportunity is notprovided for drying out the shoes, theobjectionable deterioration of the shoe thread which would otherwisetake place is prevented or retarded or minimized, thereby insuring thatthe shoe its strength and giving particularly under unfavorableconditions of use. The welt thread, which is employed for sewing theuppers of the shoe to the welt and which is close to the foot of thewearer so that it is kept Warm and, in warm or humid weather, iskeptmoist by perspiration is nevertheless preserved againstobjectionable deterioration by micro-organisms which gainaccess'to itand which would otherwise cause more rapid deterioration of the shoethread. Similarly the shoe threads used for sewing the outer edge of thesoles of the shoe and which are commonly exposed to the atmosphere andto dust, dirt, mud, etc. both on the top and the bottom of-the sole arepreserved against deterioration such as would otherwise tend to occurmore rapidly. Thus, even the unboiled shoe thread, when subjected tosuch adverse conditions in. the shoe, is comparable with or may even besuperior to the ordinary boiled shoe thread; While the boiled shoethread which is preserved in accordance with the present invention willbe materially improved in its resistance to such deterioration. Thepresent invention accordingly makes it'5possible to insure that highgrade'shoes made of high grade leather can be sewed together with theimproved shoe thread tion, thereby insuring the maximum life and utilityof the shoe as a whole.

The shoes sewed with the new linen shoe of the present inventhread arenot claimed herein but are claimed in m divisional application, Serial No. 530,- 154 ed April 14, 1931.

I claim:

-1. A linen shoe thread having a small amount of a poisoning ordehydrating disinfectant incorporated therein to preserve the shoevthread against objectionable deterioration by micro-organisms in streetdirt and the like.

2. An unboiled linen shoe thread containing the normal non-celluloseconstituents of the flax fiber and having a small amount of a poisoningor dehydrating disinfectant incorporated therein to preserve the shoethread against objectionable deterioration by micro-organisms in streetdirt and the like.

3. A linen shoe thread having a small amount of a triphenyl methane dyeincorporated therein to preserve the shoe thread against objectionabledeterioration by micro-organisms in street dirt and the like.

4. A linen shoe thread having a small amount of Brillant Green dyeincorporated therein to preserve the shoe thread against objectionabledeteriorationby micro-organisms in street dirt and the like.

5. An unboiled linen shoe thread containing the normal non-celluloseconstituents of flax fiber andhaving a small amount, of

ture; 2 r

WALTER W. EVANS.

